1. Technical Field
The present invention relates to a method of outputting an input position of a touch panel for detecting an input operation on the touch panel in orthogonal X and Y directions and outputting the input position. In particular, the present invention relates to a method of outputting an input position of a touch panel for outputting an input position even when input operations are made on a plurality of points on the touch panel.
2. Description of the Related Art
A touch panel that is combined with a liquid crystal display or other display panel for displaying icons, detects an input operation on the icons, and outputs the input position has been conventionally known. Such a type of touch panel 100 will be described below with reference to FIG. 9. The touch panel 100 includes a plurality of light emitting elements 104, 104, . . . which are attached at regular intervals along two sides in orthogonal X and Y directions in a rectangular frame 101. All the light emitting elements 104 emit light in succession along the X and Y directions, so that X scan optical paths and Y scan optical paths are formed in a matrix pattern in an instruction input area 101A inside the rectangular frame 101.
A plurality of light receiving elements 105, 105, . . . are attached to the rectangular frame 101 at positions opposed to the respective light emitting elements 104 across the instruction input area 101A. The light receiving elements 105 are configured to receive light beams emitted from the opposed light emitting elements 104. When there is no input operation, all the light receiving elements 105, 105, . . . receive the light beams at the emission timing of the opposed light emitting elements 104 within a scan cycle where all the light emitting elements 104, 104, . . . emit light in succession.
A liquid crystal display panel 103 for showing displays 102 such as icons is arranged inside the instruction input area 101A of the rectangular frame 101. An operator makes an input operation by bringing a pen, finger, or other operating member closer, using the displays 102 as guidelines. When the operator brings the operating member closer to a desired display 102, the optical paths that pass the input position are blocked. The light receiving elements 105 on those optical paths do not receive light at the emission timing of the opposed light emitting elements 104, from which the x- and y-coordinates of the input position are detected. The input position expressed by the x- and y-coordinates is output to a not-shown processing apparatus. The regions 106 where the icons 102 are displayed are previously associated with predetermined commands which are represented by the icons 102. Receiving the input position in a certain region 106 from the touch panel 100, the processing apparatus performs the processing represented by the icon 102 that is associated with the region 106.
Such a touch panel 100 is not capable of identifying input positions when input operations are simultaneously made on two or more different positions in the instruction input area 101A. For example, as shown in the diagram, simultaneous input operations on two locations “a” and “b” block two optical paths in the X and Y directions each. The input positions are indistinguishable from those of input operations on “c” and “d,” and it has been not possible for the touch panel 100 to identify and output the input positions.
In order to solve the problem, the present assignee has filed a patent application for a method of outputting an input position of a touch panel, the method including: establishing a region 107 of composite output mode in an instruction input area 101A as shown in FIG. 10; and outputting input positions of two simultaneous input operations (Japanese Patent No. 3986994 (paragraphs [0048] to [0052] and FIG. 3)). According to the method of outputting an input position, when optical paths that pass the certain region 107 in the instruction input area 101A are blocked, an input position in the region 107 identified from the blocked position is output as a first input position. An input position detected from the instruction input area 101A other than the region 107 is further output as a second input position. That is, when making simultaneous inputs on two positions, the operator makes the input operation by selecting any one of icons 108 displayed in the certain region 107 and simultaneously selecting an icon 109 displayed outside the region 107.
The present assignee has also filed a patent application for a method of outputting an input position of a touch panel, the method including: storing a first input position that is detected first in an input region; when a second input position different from the first input position is detected, estimating a direction of the second input position from the first input position and monitoring movement of the second input position; and outputting the first input position and the second input position simultaneously (Japanese Patent Application Publication No. 2009-301250 (paragraphs [0014] and [0015] and FIG. 1)).
According to the method of outputting an input position described in Japanese Patent No. 3986994, the instruction input area 101A includes the region 107 which is intended for the acceptance of two input positions. When an input operation on a single position is intended, the operator therefore needs to inconveniently avoid the region 107 when making the input operation. If an input operation is accidentally made on the region 107, the touch panel waits for an input operation on another input position. There has thus been the problem that no input position will be output unless input operations are made on two positions.
The method of outputting an input position described in Japanese Patent Application Publication No. 2009-301250 outputs two different input positions. When a foreign object is placed on a position other than the intended input positions of the operator's input operations or when the operator's elbow or sleeve approaches, such a position can be misidentified as an input position. There have thus been the problems that a command that is associated with a combination of two input positions including the misidentified one may be executed, and that a command associated with the input positions of the intended input operations may fail to be executed.
It is extremely difficult for an operator to make simultaneous input operations on three or more different positions. No command is thus assumed or associated with such input operations. An input operation on the touch panel, however, can be accompanied by the touching of more than one location such as elbows and sleeves aside from the input position of the input operation, resulting in the detection of three or more input positions. In such a case, there has been no other way than to make an input error display to inform the operator and prompt the operator to make an input operation again.
In addition, the method of outputting an input position described in Japanese Patent Application Publication No. 2009-301250 is not capable of detection and entails error processing when the two different input positions of the simultaneous input operations fall on the same axis, overlapping in the X direction or Y direction.